This invention relates to a hollow keel heat exchanger for marine craft. More particularly, this invention relates to a marine vessel having a non-metallic hull and a self-contained and protected sea water heat exchanger.
Marine craft driven by internal combustion engines require cooling systems for the engine. Sea water has been used for this purpose as described by Morgan in U.S. Pat. Nos. 968,385 and Barlow et al in 1,099,684, but there are serious drawbacks to this because of the corrosive nature of sea water.
To prevent corrosive attack in the engine interior, marine engines have been equipped with closed-loop, fresh water circulating cooling systems which are cooled by a sea water heat exchanger generally having its own pump for circulating sea water through the heat exchanger. It has been proposed to locate a portion of the fresh water loop on the exterior of the hull but the possibility for damage or destruction is great if the craft runs aground or strikes a submerged article. U.S. Pat. Nos. 2,258,526 to Walter, 2,382,218 to Fernstrum, 2,682,852 to Ruffolo, 2,612,858 to Mairs, are typical of cooling pipes outside the protection of the hull.
It has also been proposed to circulate the fresh water in direct contact with a submerged portion of the hull. However, this requires that the hull be made of a material of high thermal conductivity such as metal (see for example U.S. Pat. Nos. 2,387,700 to Cribb and 2,976,834 to Waldron et al) and is not feasible with materials of low thermal conductivity such as wood or fiber reinforced plastics now widely used in boat building.
The present invention overcomes the drawbacks to prior proposals and provides a simple, efficient and protected heat exchanger especially for marine craft with non-metallic hulls.